Are Ruddertwin flywheels cast Iron or cast steel?

[Monte NZ]

Hi all

The reason I ask, is that we are looking at casting a replacement flywheel for a friends motor, as the original has been lost.

My idea was to use my flywheel as a pattern to cast a new one.

Thanks for any advice.

Monte NZ

[crosbyman]

sounds complicated.. any magnets in that FW….

tried classifieds ??

Joining AOMCI has priviledges 🙂

[outboardnut]

I would contact Christopher Scratch

[Finn Freeman]

I agree that Christopher Scratch would probably know best.  He is the Elto special interest group leader. You can find him in the SIG section on the inner sanctum, and his contact information is in the SIG list in the magazine.

[Monte NZ]

Thanks for your replies boys.

In reply Crosbyman, fortunately there aren’t any magnets and my friend has access to an engineering shop, so the machining shouldn’t be a problem………the chances of finding a secondhand one here is extremely unlikely.

Thanks outboardnut and Finn Freeman for your suggestion of contacting Christopher Scratch……..I will give him a call.

Thanks again

Monte NZ

 

 

[joecb]

Monte, Chris is defiantly the fellow that can give you the info. I always appreciate the initiative when the solution is… “we will make one”.  Just be aware that that flywheel has the timer actuating eccentric machined on the underside, an integral part of the hub casting. However, for your purposes, I think that a separate eccentric could be attached to the lower surface of the flywheel. The stroke on the eccentric is very short, just enough to trip the timer. Chris will know if there is any rotational timing issue between features on the flywheel and the eccentric.

Good luck with your project.

Joe B

PS, as for shipping costs to NZ…any deals between Canada and NZ? Maybe Chris can ship the parts.

[need2fish]

Check Doug Penn @https://www.oldoutboard.com/

Doug and his family have spent decades collecting parts.

[PM T2]

For what its worth, I have been in contact with the gentleman who had the question. It was never stated specifically what the flywheels were made of originally. It would take spectrometer testing to verify the actual elements contained in a given sample of flywheel metal. That being say-ed, I would suggest that a flywheel cast in ductile iron is as good a replacement as you will find. It doesn’t have to spin much over 1200 RPM.

With respect to the eccentric orientation (its not really an eccentric – it’s an offset circle is what it is), a good pattern maker can build whatever you want. I’ll make some assumptions here and wager that if the conversation has gotten as far as considering the use of  a good original part as a pattern to cast a fresh one that the methodology has been discussed and decided upon. I’d just volunteer that there should be some additional material present in the casting that allows for shrinkage and also to accurately machine the new casting. Spraying wax on the pattern part is one way to do this in a uniform manner. The key thing is to duplicate the circular off-set orientation in the reproduction part to make it the same as the original. Its perfectly round so as long as you duplicate the orientation and diameter of the original, your timing should be fine.

If you want to be daring and add some pep to her step – machine the off-set in such a way that you advance the timing a couple of degrees. I’m only kidding – don’t actually do it. But that is part of how the Speedsters generate their higher revs and additional power… and its why a Ruddertwin flywheel won’t work worth a damn on a Speedster.

Regarding shipping parts overseas – I’ve had a bad experience with a person in the land Down Under ripping me off, so that activity is off my list of things to ever do again.

Best,
PM T2

He's livin' in his own private Idaho..... I hope to go out quietly in my sleep, like my grand-dad did..... and not screaming, like the passengers in his car...

[Monte NZ]

Hi All and thanks for your replies.

Joe, with you, outboard nut and finn freeman’s suggestions, it looks like Chris Scratch is the one to contact! Your suggestions on the machining of the eccentric had been in the back of my mind…….. I have seen another Ruddertwin down country, which I think had a problem with the keyway, in that I noticed what appeared to be an insert of about 2 inches in diameter held in place by a series of cap screws……..it was a very neat job. I will go and have a closer look and take some photos, when I’m down there at Easter. Hopefully the owner wont mind  me lifting the flywheel to see what the story is regarding the eccentric. Regarding shipping deals to NZ, I don’t know of anything from Canada and as you can imagine the current costs of postage going on weight would be “mind blowing” going on what it  cost to have a 1921 Evinrude tank mailed out to another outboard collector here recently.

needtofish, I was wondering about contacting Doug……..like you said, he would have had a lot of contact with the Ruddertwins.

pmt2, thanks for your comments and suggestion too. You are correct, in that the cam is an offset circle (not an eccentric) and may I add, that I’m very sorry to hear  of your unfortunate experience of being ripped off………very embarrassing to me,  in that it was someone “down under” where I am……….very sad indeed! I can quite understand you not wanting to experience that again!

 

 

Thanks one again……much appreciated all of you and Chris.

Monte NZ

PS 1  Since receiving your posts, I contacted Chris Scratch, who was very helpful.  Basically, he felt that there wasn’t any need to get involved it metallurgy and that they cast them in what was called nickel steel, but felt that ductile iron would be successful……….he did mention too, that old rowboat motors flywheels were cast iron or what he thought was called gray iron.

PS 2 It could be an interesting project………will keep you posted.

 

[joecb]

Just a thought,  If one didn’t mind making a whole pile of chips, that flywheel could be machined from low carbon steel.

Joe

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